I. Field of the Invention:
This invention relates generally to seed planting apparatus, and more particularly to an improved planter which may be used to accurately and precisely position a crop seed into the ground at a spacing which can be readily adjusted in a first embodiment, within limits, by the simple adjustment of a pulley size, and in a second embodiment by the adjustment of a hydraulic flow control valve.
II. Discussion of the Prior Art:
In the Adams U.S. Pat. No. 3,561,380, there is described a seed planter which incorporates an endless belt as a conveyor, the belt having a plurality of openings call "seed pockets" formed therealong for receiving individual seeds from a hopper and for carrying those seeds to a location where the conveyor belt engages the ground. Ideally, the conveyor belt is driven so that the ground-engaging flight is moving in a direction opposite to the direction of movement of the seed planter and at the same relative velocity so that the effective ground speed of the conveyor is zero. Associated with the conveyor belt is a further belt having protuberances thereon at a spacing corresponding to the spacing between the pockets on the belt. The protuberances are configured to enter the openings forming the seed pockets and to force the seeds therefrom into the ground.
While, in theory, the device described in the Adams U.S. Pat. No. 3,561,380 may appear operable, in practice, a device made in accordance with this patent would be of limited operability. First of all, the manner in which the hopper is positioned relative to the seed-receiving belt necessarily limits the capacity of the hopper. Accordingly, it is necessary to refill the hopper at more frequent intervals than would otherwise be required. Also, practical difficulties are encountered in loading the seed pockets in the belt from the hopper and in unloading same when it is considered that the conveyor belt must be moving at the vehicle's ground speed to maintain the necessary zero relative motion between ground and the belt. The system of the Adams U.S. Pat. No. 3,561,380 also suffers from the defect in that the spacing between adjacent seeds cannot be controlled and is strictly limited to the spacing between seed openings on the belt itself. As such, the device of the Adams patent cannot be used to plant more than one commodity if those commodities require different seed-to-seed spacing.